Research on artificial sweeteners’ effect on cancer cells – Dr Armorel Van Eyk
Dr Armorel Van Eyk
- Division of Pharmacology, Department of Pharmacy and Pharmacology, Faculty of Health Sciences, University of the Witwatersrand
- Biography of Dr Van Eyk
The diffusion of food additives and possible carcinogens across biological membranes and the study of the effects that these compounds have on the growth, morphology, level of differentiation, apoptosis and damage to DNA of human cell lines.
Sugar substitutes are used in the food and beverage industries as a replacement for sugar but without the added calories. These agents are either of natural origin (e.g. mannitol, xylitol, fructose, glucose, stevia) or are synthetic (e.g. aspartame, acesulfame-K, sucralose, cyclamate and saccharin). Many of them are added to drugs as well as hygiene products and are especially used in calorie reduced ‘diet products’. Artificial sweeteners especially, have been associated with potential cancer risks since their inception. Consumption of high quantities of fructose has also been associated with increased cancer risk. Within our Western society, many people are exposed to these sweetening agents and ingest them knowingly or not. The association of many of the agents with the potential to cause cancer could put the entire population at risk.
Up to now, there is a lot of conflicting evidence as to whether heavy artifical sweetener usage might increase the risk of saccharin and cyclamate, however this has not been shown to occur in humans. DNA strand breaks have been induced by sodium cyclamate and aneuploid cells were noticed after 3-6 days of exposure of leukocytes to the sweetener. Exposure of monkeys over a long period of time to high doses of cyclamate (50mg/kg), resulted in the appearance of malignancies (adenocarcinoma of the colon, hepatocellular carcinoma and well-differentiated pappilary adenocarcinoma of th eprostate (100mg/kg). Benign tumours were also recorded (thyroid gland adenoma and leiomyoma of the uterus). Exposure to aspartame has been associated with malignant cancers i.e. lymphomas, leukaemia and tumours occurring in multiple organ sites.
The chlorocarbon sucralose has been shown to cause damage to hepatocytes and has been shown to induce swollen livers and calcification of the kidneys in test animals. Chlorocarbons are associated with cancer, birth defects and immune system destruction. Lung tumours, breast tumours, and several forms of leukaemia have been associated with acesulfame-K. Because many of the artificial sweeteners have shown a potential to cause cancer in normal tissue, the question arises whether these sweeteners may induce accelerated cell changes, proliferation and further DNA alterations in cancer cells. Results from studies like these would give valuable information as to the possible effects of artificial sweeteners on cancer cells in tumours of cancer patients taking these food supplements. Cancer patients that are in remission might also be at a greater risk of their cancers recurring if these additives are shown to increase cancer cell proliferation and increased DNA alterations.
The use of sugar substitutes has become more popular over the years due to the ncreased levels of obesity and diabetes in the human population. The number of patients diagnosed with cancer has also been steadily increasing over the years. People in the Western countries are exposed to the Western diet which is rich in food additives and artificial agents used to make the food taste and look better and also to preserve it for a longer period of time.
This project hope to provide some additional information on how these agents may affect cancer cells and result in the possible increased proliferation and increased damage to already unstable DNA within cancer cells. People may consume a large quantity of these sugar substitutes unknowingly during their lifetime and it is of importance to indicate the possible effect these agents may have on cancer cells that may be present in the body.
Results found up to the present date indicate the possibility that some artificial sweeteners may indeed have adverse effects on individual cells. Some consistent patterns have developed in the project so far, indicating that certain types of cancer cells are affected to a much greater degree than others. The proliferative effect at low artificial sweetener concentrations are also consistently observed in all the cancer cell lines tested except for the neuroblastoma cells. These sweeteners seem to accumulate in cells at higher concentrations in the form of localized dispersed black dots and the cells have a consistent altered morphology.
Previous studies performed on pancreatic cancer cells by other researchers have indicated that all forms of sugar have the ability to promote cancer, although to different extent. It was shown that fructose in particular have the ability to potentially increase cancer risk because cancer cells seemed to prefer fructose to other sugars to proliferate by increasing the synthesis of nucleic acids. Potential ways in which fructose can promote cancer growth involve either altered cellular metabolism, formation of free radicals, damage to DNA or initiating inflammation. The metabolism of the sugar is of utmost importance for cellular proliferation. Glucose and sucrose are used by cancer cells to proliferate however, it seems that fructose causes cancer cells to thrive and proliferate frofoundly even at high concentrations. These finds were confirmed in the current study on two colon cancer cell lines (Caco-2 and HT-29) as well as a non-cancerous human embryonic kidney cell line (HEK-293). Although fructose is thought of as a healthy sugar occurring naturally in fruits, it occurs commonly in many processed foods. This results in the public being exposed to fructose in high doses without being aware of it. In other countries especially consumption of food with fructose content can be greatly in excess of the upper limit.
In the current study it was found that 2 of the sugar alcohols (mannitol and xylitol) also used as sugar substitutes and the new natural sugar substitute stevia have the possibility to slightly increase cell proliferation at lower concentrations, however cells decreased in proliferation at higher concentrations of xylitol and mannitol. In the previous report it was indicated that Stevia showed cell toxicity at higher concentrations. It is of great importance to take note of any evidence indicating the possibility that these food additives might induce proliferation of cells at lower concentrations and might adversely affect DNA in cells. Providing more information on the possible adverse effects that these agents might have in the body will provide a person with the knowledge to make informed decisions on whether they want to consume these agents or not.
Conferences and abstracts
- AD van Eyk, N Dahan-Farkas, C Rieger and M Masuku. The Effect of 5 Artificial Sweeteners on Caco-2, HT-29 and HEK-293 Cells. 6th IPPCS Congress, 25-27 September 2011, Coastlands on the Ridge Durban, KwaZulu-Natal, South Africa.
- AD van Eyk, N Dahan-Farkas, J Langlands and S Aboo. The Effect of 5 Artificial Sweeteners on Caco-2, HT-29 and SH-SY5Y cell lines. 46th Annual Congress of the SASBCP, 30 September-October 2012, Sanlam Auditorium, University of Pretoria.